Needed : upgraded web tool for molding

nicolas.beaudoin_MI — Thu, 12 Oct 2023 14:46:19 GMT

Hella all.

When designing parts for any type of molding, polymer injection, die casting, etc., one of the major considerations when implementing web-like feature to reinforce the back side of a part is the width of the rib where it contacts the main shell of the part. There are several reasons for that, among which is ensuring that the rib will be filled out adequately by the material and the sink marks caused by the increased thickness of the shell at the base of the rib. There are rules we can follow to mitigate theses problems.

The problem I am running in to with Fusion 360’s web function is that I don’t have proper control over the width of the ribs where they contact the shell.

For the next section of this post, please keep in mind that the measurements are fictitious, but are representative of reality.

So, if use the web function and define the thickness from the base of the rib, I can get a condition like the following :

web from base

In a condition like this, I may not be able to fill the rib on the right because the root of the rib is too narrow.

In the example below, I define the top as the reference, which is the sketch plane, I can get a condition like this :

web from top

In this example, the root of the rib is so wide, that I will get significant sink marks on the opposite side of the shell. Notice on the rib on the right that the width of the rib at the base is 1,8 mm when projecting on the sketch plane, but in actuality, it is the width projected on the surface that dictates the sink marks. In this case, I will get major sink marks.

What we need for forming fabrication, such as molding and die casting, is a tool which would be a hybrid between the emboss and the web functions. The emboss tool projects the sketch on the base surface and, based on my experimentation, the root of the emboss extrusion respects quite well the desired width. The problem with the emboss tool is that it extrudes the profile normal to the base surface. That is where the web function additional parameters would be helpful, to define a direction of extrusion, the draft angle and fillets. It would be even better to be able to use line profiles as sketch feature and assign width, like web.

The goal is to be able to achieve web configurations like the next two pictures.

needed tool using sketch plane directionneeded tool using arbitrary pull direction

I am able to achieve the desired result following a workflow involving emboss, offset surfaces, multiple ruled surfaces, stitching and boundary fill. This workflow quickly becomes very tedious. I know this could be automated. I know it is a feature that should be included in Fusion 360, at least in the Plastic module.

Please consider this feature request.

Best regards.

Re: Needed : upgraded web tool for molding

nicolas.beaudoin_MI — Thu, 12 Oct 2023 15:45:53 GMT

I am also interested in knowing if someone in the community has scripted a tool that does this.

topic Needed : upgraded web tool for molding in Fusion Design, Validate & Document Forum

Needed : upgraded web tool for molding

Re: Needed : upgraded web tool for molding